In the field of print reproduction, there is a demand for improvements in the operational efficiency of the photographic platemaking process in order to cope with the diversity and complexity of the print.
In particular, improvements in the operational efficiency have been provided for in the operations of lay-out process and contact work by carrying out these operations in brighter environments, and there have, therefore, been developments in exposure printers and in silver halide photographic materials for platemaking which can be handled in an environment which can essentially be referred to as a bright room environment.
The bright-room silver halide photographic materials referred to herein are photographic materials with which light of a wavelength of 400 nm or more and which does not include any ultraviolet component is used as the safelight.
Bright-room silver halide photographic materials used in lay-out process and contact work are photographic materials used in negative/positive conversion or positive/negative conversion by the contact exposure of an original with a silver halide photographic material for contact work, where the original is a developed film on which a character or halftone image has been formed. These photographic materials should have the following characteristics:
(1) a negative/positive conversion performance such that the halftone image and the line and character images respectively correspond to the halftone surface area and the line width and character-image width, and PA1 (2) a performance allowing tone adjustment in the halftone image and line-width adjustment in the character and line images. PA1 (A) at least: one compound selected from compounds represented by formulae (I), (II) and (III); and PA1 (B) at least one compound selected from compounds represented by formulae (A), (B) and (C): ##STR2## wherein X represents OR.sub.11 or N(R.sub.15)R.sub.16 ; R.sub.11 represents a hydrogen atom or a group which can become a hydrogen atom by hydrolysis; R.sub.12, R.sub.13 and R.sub.14 each represents a hydrogen atom or a substituent; R.sub.12, R.sub.13 and R.sub.14 may be the same or different, and when any two of R.sub.12, R.sub.13 and R.sub.14 have been substituted on neighboring carbon atoms in the benzene ring, they may link to form a carbocyclic or heterocyclic 5- to 7-membered ring wherein the ring may be saturated or unsaturated; R.sub.15 and R.sub.16 each represents a hydrogen atom, an alkyl group, an aryl group, an alkylsulfonyl group, an arylsulfonyl group, an alkylcarbonyl group, an arylcarbonyl group or a carbamoyl group, each of which may be substituted or unsubstituted; R.sub.15 and R.sub.16 may be identical or different and may link to form a nitrogen-containing heterocyclic ring; Y represents a group promoting adsorption onto the silver halide, L represents a divalent linking group; and m represents 0 or 1; ##STR3## wherein R.sub.21, R.sub.22, R.sub.23 and R.sub.24 each represents a hydrogen atom, a hydroxyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted alkylthio group, a substituted or unsubstituted arylthio group, a halogen atom, a primary, secondary or tertiary amino group, a substituted or unsubstituted carboxamido group, a substituted or unsubstituted sulfonamido group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a 5-membered or 6-membered heterocyclic group containing at least one N, O or S atom, a formyl group, a keto group, a sulfonic acid group, a carboxylic acid group, a substituted or unsubstituted alkylsulfonyl group or a substituted or unsubstituted arylsulfonyl group; ##STR4## wherein W represents OH or N(R.sub.31)R.sub.32 ; R.sub.31 and R.sub.32 each represents a hydrogen atom, an alkyl group, an aryl group, an alkylsulfonyl group, an arylsulfonyl group, an alkylcarbonyl group, an arylcarbonyl group or a carbamoyl group, each of which may be substituted or unsubstituted; R.sub.31 and R.sub.32 may be identical or different and may link to form a nitrogen-containing hetero ring; and R.sub.33, R.sub.34, R.sub.35 and R.sub.36 each represents a hydrogen atom or a substituent group; R.sub.33, R.sub.34, R.sub.35 and R.sub.36 may be identical or different; R.sub.33 and R.sub.34 may link to form a 5- to 7-membered carbocyclic or heterocyclic ring wherein the ring is saturated or unsaturated; ##STR5## wherein Z represents an alkyl group having 1 to 18 carbon atoms, an aryl group having 6 to 18 carbon atoms or a heterocyclic group; Y represents an aromatic ring having 6 to 18 carbon atoms or atoms necessary to form a heterocyclic ring; Z and Y may be substituted or unsubstituted; M represents a metal atom or an organic cation; and n represents an integer of 2 to 10.
Corresponding bright-room silver halide photographic materials for contact work have already been proposed.
However, tone adjustment of the halftone image by bright-room contact work using bright-room silver halide photographic materials is disadvantageous because, when there has been underexposure, marked deterioration is likely to occur in the density of the portion which is essentially expected to turn black by developing the whole surface.
Methods for obtaining a contrasty Dm (maximum density on characteristic curve) increase by including a developing agent in the silver halide photographic material have been disclosed in, for example, U.S. Pat. No. 4,617,258, JP-A-59-171947, JP-A-59-206828 and JP-A-1-262533 (the term "JP-A" as used herein means an "unexamined published Japanese patent application"), but these do not satisfy all the safelight, storage stability and Dm performance criteria. Further, JP-A-1-237538 discloses a method for improving the storage stability by including thiosulfinic acid in the silver halide photographic material.